We're a gregarious species.

It's literally hardwired into human brains.

What on earth can explain Facebook's tremendous impact?

Just yesterday, friends posted results of quizzes that purport to determine what movie musical character, alcoholic beverage, color, book and animal they most resemble.

These are real friends, mind you, not just Facebook "friends." But although I know and like these people and enjoy their real-world company, I couldn't care less that some asinine quizzes have determined that they are Mary Poppins, tequila, green, Moby Dick and aardvarks.

And yet I continue to visit Facebook. I suspect you do, too.

Why? Human beings are hardwired to be gregarious. Literally.

Tucked away in our brains' anterior cingulate cortexes and frontal insulas are von Economo neurons, a special type of brain cell we humans share with great apes, elephants and whales. Neuroscientists believe that these cells predispose us to gregarious behavior.

Gregarious, not herd.

Herding – or flocking – species hang out together. Gregarious species interact with "...social emotions such as empathy, trust, guilt, embarrassment, love – even a sense of humor," according to Ingfei Chen's article about von Economo neurons in June's Smithsonian.

That predisposition to gregariousness goes a long way toward explaining the appeal of social media.

From the days of hunter-gatherer societies, large-brained primates (like us) worked in groups. One group hunted, another group gathered. Both groups came together at the end of the day with the game and the gatherings.

The primates and the work evolved, but activities have been mainly carried out in group environments from the days of the collective mastodon hunt to the assembly line to last week's budget review meeting.

Not everyone works in a group, of course. Most artists, assassins, prospectors, mail carriers and shepherds work alone. And hermitting is a solitary vocation. But those are exceptions to a pretty universal norm of folks working with other folks. At least until recently.

Interconnectivity has, ironically, made people less connected. A three-year old study found that 9% of American workers worked in home-based businesses, and another 10% telecommuted either full time or part time. Those numbers have been trending up ever since, with a significant – though not-yet-accurately-quantified – spike in the present recession.

We believe that now as many as 25% of American workers do their jobs in home offices or workshops. The BrainPosse team is linked online from our individual work spaces. In some cases even the home office or shop is eliminated. Our freelance IT guy works out of his car. He's got phone, text and internet access, so he simply answers calls for help and drives from rescue to rescue.

There are three obvious effects of this digitally-connected, socially-disconnected environment:

1. Overhead is reduced. There is little or no unproductive expense for office space.

2. Sales of business attire have plummeted. (Though bunny slipper sales have probably soared.)

3. The need for contact hardwired into our brains is unfulfilled.

The third effect is probably a pretty significant factor behind Facebook's impact. Because the posts that greet us every time we visit the site are exactly the sort of inconsequential chatter people used to exchange in the break room, at the water cooler or in the locker room where they changed into work clothes.

It's stuff like: "Teresa is being lazy this morning," "Brent feels like he slept on a metal octopus," and "Jonathan thinks he might go to the lake." (Actual posts that were up as this was being written.)

Most of us respond with "Enjoy it, Teresa. You've earned it," "Hope you get the kinks out, Brent." and "Jonathan, I envy you." Nothing earth-shaking. Just a little contact.

That has some implications for the use of social media as a marketing communications tool.

In a previous post, Social Media Advertising ROI, we explored the abysmal results social media sites deliver for advertisers. Display ads on Facebook don't work at present, and there's no sign that their near-total ineffectiveness is going to change any time soon.

In other posts – Social Engagement, last week's The Investment in Social Networking and The Virtual Social Animal – we examined ways in which marketers can use social media effectively by participating through postings.

And that's where the von Economo neurons come in.

A marketer's social media posts should be inclusive conversations. They should invite and encourage readers to interact, participate and become part of a community which also includes the marketer's brand. Ideally, followers of the brand's page should become a community whose members supply most of the dialog. The brand itself should be personified by the company people who participate in the conversation.

There doesn't have to be a big announcement in posts. In fact, there probably shouldn't be. If the brand is adding a new benefit, the company person posting begin with: "Long days for the last month trying to redesign the crankshaft for better torque. So far we know seven ways not to do it." Then later "Took two months, but we finally got it. Check out the new design here. Let us know what you think."

It's also important to respond to followers' posts. Not as a brand, but as a person. Making prospects part of a community that your brand is also part of can form a powerful bond that translates directly into purchase decision-making.